
/* EMAIL ENCRYPTION SCRIPT */

// This script is (c) copyright 2008 by Dan Appleman under the
// GNU General Public License (http://www.gnu.org/licenses/gpl.html)
// This script is modified from an original script by Jim Tucek
// For more information, visit www.danappleman.com 
// Leave the above comments alone!
// see encryption_instructions.txt for explanation of usage

var decryption_cache = new Array();

function decrypt_string(crypted_string,n,decryption_key,just_email_address) {
	var cache_index = "'"+crypted_string+","+just_email_address+"'";

	if(decryption_cache[cache_index])					// If this string has already been decrypted, just
		return decryption_cache[cache_index];				// return the cached version.

	if(addresses[crypted_string])						// Is crypted_string an index into the addresses array
		var crypted_string = addresses[crypted_string];			// or an actual string of numbers?

	if(!crypted_string.length)						// Make sure the string is actually a string
		return "Error, not a valid index.";

	if(n == 0 || decryption_key == 0) {					// If the decryption key and n are not passed to the
		var numbers = crypted_string.split(' ');			// function, assume they are stored as the first two
		n = numbers[0];	decryption_key = numbers[1];			// numbers in crypted string.
		numbers[0] = ""; numbers[1] = "";				// Remove them from the crypted string and continue
		crypted_string = numbers.join(" ").substr(2);
	}

	var decrypted_string = '';
	var crypted_characters = crypted_string.split(' ');

	for(var i in crypted_characters) {
		var current_character = crypted_characters[i];
		var decrypted_character = exponentialModulo(current_character,n,decryption_key);
		if(just_email_address && i < 7)				// Skip 'mailto:' part
			continue;
		if(just_email_address && decrypted_character == 63)	// Stop at '?subject=....'
			break;
		decrypted_string += String.fromCharCode(decrypted_character);
	}
		decryption_cache[cache_index] = decrypted_string;			// Cache this string for any future calls

	return decrypted_string;
}

function decrypt_and_email(crypted_string,n,decryption_key) {
	if(!n || !decryption_key) { n = 0; decryption_key = 0; }
	if(!crypted_string) crypted_string = 0;

	var decrypted_string = decrypt_string(crypted_string,n,decryption_key,false);
	parent.location = decrypted_string;
}

function decrypt_and_echo(crypted_string,n,decryption_key) {
	if(!n || !decryption_key) { n = 0; decryption_key = 0; }
	if(!crypted_string) crypted_string = 0;

	var decrypted_string = decrypt_string(crypted_string,n,decryption_key,true);
	document.write(decrypted_string);
	return true;
}

// Finds base^exponent % y for large values of (base^exponent)
function exponentialModulo(base,exponent,y) {
	if (y % 2 == 0) {
		answer = 1;
		for(var i = 1; i <= y/2; i++) {
			temp = (base*base) % exponent;
			answer = (temp*answer) % exponent;
		}
	} else {
		answer = base;
		for(var i = 1; i <= y/2; i++) {
			temp = (base*base) % exponent;
			answer = (temp*answer) % exponent;
		}
	}
	return answer;
}

// Remove the comments below to improve spam resistance! 
// email addresses: 

 if(!addresses) var addresses = new Array();
addresses.push("3379 3373 1744 2837 365 1852 2478 1652 1255 2610 1718 2297 2610 1073 500 1744 2172 1671 365 2610 2837 1852 2610 1652 135 2487 641 1790 1652 135 1539 63 641 2297 563 456 2172 2610 2478 867 1025 365 2172 1852 1671 1985 3247 2172 1671 365 2610 365 2399 2172 1985 2338 2399 2033 2297 365 135 365 2172 641");  // [0] chuck - at - medicalcorps.org
